Flavored e-cigarettes, the "sugar-coated bullet" in e-cigarettes

Author: Xiao Dan, Director of the Department of Tobacco Control and Respiratory Disease Prevention and Control, China-Japan Friendship Hospital, Researcher

Reviewer: Tang Qin, Deputy Secretary-General of the Science Popularization Expert Committee of the Chinese Medical Association, Researcher

Beware of tobacco "bombs"

Are e-cigarettes, which were called "safe tobacco substitutes" when they first entered the market, really safe? Numerous research results have given the answer.

To know the facts, we need to know the reasons. If we want to know how e-cigarettes cause harm, we must first understand the principles of their use. In layman's terms, let's first understand how this thing that does not require ignition can produce smoke.

Electronic cigarettes are electronic products that imitate cigarettes, mostly composed of smoke liquid (containing nicotine, flavors, solvent propylene glycol, etc.), power supply, atomization components and control unit. Under the power supply and control unit, the smoke liquid is heated and atomized to form smoke and inhalable aerosol (in layman's terms, smoke), thus producing an experience similar to using cigarettes.

Neither the smoke nor the aerosols that people inhale when using e-cigarettes are safe.

E-liquid contains carcinogens

E-cigarette liquid contains carbonyl compounds such as formaldehyde and acetaldehyde. Formaldehyde is highly carcinogenic and inhibits the movement of cilia in respiratory epithelial cells, thus causing damage to the respiratory tract. Studies have found that as the temperature of the liquid increases, the concentration of carbonyl compounds such as formaldehyde and acetaldehyde increases significantly.

In addition, tobacco-specific nitrosamines have been detected in e-cigarette liquids, and some nitrosamine components are listed as Class I carcinogens by the World Health Organization's International Agency for Research on Cancer.

Aerosols contain toxic substances

E-cigarette aerosols also contain toxic substances. Heavy metal elements such as tin, copper, nickel, arsenic, and copper can be detected in aerosols. As heavy metal elements accumulate in the human body, they can cause damage to health, especially the nervous system. Although the mass of nanoparticles in e-cigarette aerosols is very small, they may cause greater harm to health after being inhaled into the lungs.

Smoke is cytotoxic

Electronic cigarette smoke is cytotoxic. Cells exposed to electronic cigarette smoke are more susceptible to DNA damage and death. The harmful components contained in the electronic cigarette aerosol can damage the function of the cilia of normal human bronchial epithelial cells. Long-term exposure to such substances can cause damage to human health, especially lung health.

In addition, some researchers have found that e-cigarette liquid and aerosol have obvious cytotoxicity to human lung fibroblasts, lung epithelial cells (A549) and human embryonic stem cells, and e-cigarettes of different brands and flavors are cytotoxic, which can lead to cell apoptosis, cell damage, etc. People should be aware of the fact that e-cigarettes can cause harm to health.

Distinguishing the “Sugar Coating” of Seasoning

The "Electronic Cigarette Management Measures" (hereinafter referred to as the "Management Measures") issued by the State Tobacco Monopoly Administration on March 11, 2022 stipulates that the sale of flavored electronic cigarettes other than tobacco flavors and electronic cigarettes that can add self-atomizers is prohibited.

What is it about the “fragrance” of e-cigarettes that is more harmful than the e-cigarettes themselves?

The obvious harm is that flavored e-cigarettes have led to a clear upward trend in the number of teenagers using e-cigarettes. Different flavors of flavorings, such as mint and fruit flavors, are added to e-cigarettes, which greatly increase their appeal to teenagers. Studies have shown that after teenagers use e-cigarettes, the risk of becoming cigarette users in the future is more than twice that of those who never use e-cigarettes.

Figure 1 Flavored e-cigarettes

(Drawing by the author)

E-cigarette flavorings can also harm the health of every user. A variety of e-cigarette flavorings can be seen on the market, but the ingredients of these flavorings are unclear. Manufacturers usually do not provide the formula of the flavorings, claiming that it is a "trade secret." Some manufacturers will mark these flavorings as safe additives or food grade.

Food-grade flavorings sound safe and risk-free. However, it should be noted that food enters the digestive system after entering the mouth, while smoke enters the respiratory system after entering the mouth, so the safety standards of the two are naturally different.

Figure 2 (drawn by the author)

Some researchers have tested e-cigarettes containing different types and concentrations of flavoring agents. The results show that the free radical substances produced in e-cigarette smoke are positively correlated with the concentration of flavoring agents, and as the concentration of flavoring agents increases, the amount of free radicals released also increases. Free radicals can cause oxidative stress in the human body, and oxidative stress plays an important role in pathological processes such as inflammation, endothelial dysfunction, lipid abnormalities, and platelet activation.

Aren’t these flavored e-cigarettes just sugar-coated bullets?

The variety of novel flavors makes e-cigarettes very attractive. In fact, the tobacco industry has long produced mint-flavored cigarettes, and the popularity of flavored e-cigarettes is just the result of a repetition of the old trick.

Fortunately, flavored e-cigarettes will be withdrawn from the market with the implementation of the "National Standard for E-cigarettes". But no one can be sure whether such a trick will make a comeback in a new look.

The most effective way to deal with potentially misleading marketing campaigns and avoid falling into traps is to stay away from any form of tobacco and eliminate any degree of harm from smoking.